碳纳米管/丁苯橡胶复合材料的电学性能

采用喷雾干燥法可制备不同配比的碳纳米管（Carbon nanotubes,CNTs）/粉末丁苯橡胶复合材料,观察CNTs在橡胶基体中的分散情况,检测复合材料的导电性能及介电性能,并进行了简要的理论分析。结果表明:CNTs在橡胶基体中获得了充分均匀的分散,有利于CNTs改性补强作用的发挥。与纯胶样品及填充炭黑（Carbon black,CB）样品相比, 填充CNTs样品在8~18GHz下具有较高的介电常数及低介电损耗。随着CNTs加入量的增加,CNTs/粉末丁苯橡胶复合材料的电导率逐渐升高,当CNTs加入量为60phr（per hundred rubber）时,与纯胶样品及添加60phr CB样品相比,电导率提高近10个数量级;复合材料内部导电同时存在隧道导电机制和渗逾导电机制。采用喷雾干燥法制备的CNTs/粉末丁苯橡胶复合材料,将是一种综合性能良好的新型纳米复合材料,有望在抗静电橡胶、电磁屏蔽及介电材料等领域获得应用。      

氯化聚乙烯/碳纳米管复合材料的制备及其性能研究

以三氯化铝(AlCl3)作催化剂,将多壁碳纳米管(MWNTS)悬浮在氯仿(CHCl3)溶液中,通过亲电加成反应,对MWNTS进行了侧壁化学修饰,并对化学修饰后的MWNTS作了红外光谱的分析.分别采用机械共混法和溶液共沉淀法制备了CPE/CNTs复合材料,对CPE/CNTs复合材料进行了拉伸性能及流变性能的测试,并利用扫描电子显微镜(SEM)观察了CPE/CNTs复合材料拉伸断面的形貌特征.结果表明:CPE/CNTs复合材料的拉伸强度随碳纳米管加入量的增加而增大,当碳纳米管的加入量为5份时,其拉伸强度最大,与纯氯化聚乙烯的拉伸强度相比,提高了75%;化学修饰后的碳纳米管在氯化聚乙烯基体中有了较好的分散性和相容性;CPE/CNTs复合材料的表观粘度随碳纳米管加入量的增加而逐渐增大.     

CNTs/PPG/PP复合材料的非等温结晶行为

采用差示扫描量热法(DSC)研究了碳纳米管(CNTs)加入量和降温速率对CNTs/接枝马来酸酐聚丙烯(PPG)/聚丙烯(PP)复合材料(CNTs/PPG/PP)的非等温结晶过程的影响,并采用Jeziorny法对DSC结果进行动力学分析。结果表明:当降温速率为20℃/min时,加入CNTs可提高复合材料的结晶温度,当CNTs加入量为1.0%(wt,质量分数)条件下,复合材料的结晶峰温度为117.6℃,比未加CNTs时提高了2.0℃,CNTs的加入同时还使得复合材料结晶度增大,结晶速率加快,且均随着CNTs加入量的增加而增大;CNTs起到了异相形核作用,改变了PP基的形核方式和晶体长大方式;降温速率的增大使得复合材料将在更低的温度下结晶,结晶度增大。     

氮化铝/氮化硼/碳纳米管/硅橡胶复合材料的力致填料取向对导热性能的影响

随着科学技术的发展,电子元器件发热量大幅度增加,因此开发兼具高导热和高绝缘性能材料日益迫切。以甲基乙烯基硅橡胶（SR）为基体,碳纳米管（CNTs）、六方氮化硼（BN）以及氮化铝（AlN）为导热填料,通过机械共混法制备导热复合材料。研究3种导热填料复配对复合材料的导热性能、绝缘性能和力学性能的影响,研究填料取向对复合材料导热性能的影响,研究材料表面温升与加热时间的关系。采用Agari模型预测复合材料的理论热导率。通过热红成像、扫描电子显微镜、X射线衍射分析、热重分析等对复合材料进行表征。结果表明：随着复配导热填料中AlN用量的减少,BN和CNT_S用量的增加,复合材料的热导率逐渐升高;当AlN为80 phr,BN为68 phr,CNTs为2 phr时,复合材料的垂直热导率为1.857 W·m^-1·K^-1,平行热导率为2.853 W·m^-1·K^-1,体积电阻率为2.18×10¹² Ω·cm,拉伸强度达4.3 MPa,复合材料的综合性能较好。     

旋转摩擦挤压法制备CNTs/Mg复合材料的组织和力学性能

通过显微硬度和抗拉强度试验、X射线衍射仪、扫描电镜和金相显微镜观察,研究经旋转摩擦挤压法制备的CNTs/Mg复合材料的组织及性能。结果表明:CNTs/Mg复合材料的组织为细小等轴晶,且随着CNTs含量的增加,复合材料晶粒尺寸逐渐细化,当CNTs含量为5%时,晶粒尺寸最小,由63μm减小至3.79μm,为AZ91基材晶粒尺寸的6.01%。经过旋转摩擦挤压加工后基材内第二相β-Al12Mg17相的量减少,CNTs的加入使复合材料中出现了Al4C3相,且第二相β-Al12Mg17相网状结构消失。加工后的镁合金抗拉强度提高,最大值为330.9 MPa,较原基材提高了90.6%,当CNTs含量小于2%时,复合材料强度高于原基材。复合材料硬度随着CNTs含量的增加呈先增加后降低的趋势,当CNTs含量为2%时,硬度最高,达101.3HV,比AZ91基材提高了40.3%。     

机械混炼对碳纳米管/丁苯橡胶复合材料的影响

为研究机械混炼对碳纳米管(CNTs)/粉末丁苯橡胶(SBR)复合材料性能的影响,从而获得性能优异的CNTs/SBR复合材料,联合采用喷雾干燥法和机械混炼法,制备高填充量CNTs/SBR复合材料.将喷雾干燥法制备的CNTs/粉末SBR复合材料在开炼机上机械混炼,对比分析混炼前后试样的物理和力学等相关性能,并对其微观形貌进行检测.结果表明,机械混炼使CNTs获得进一步的分散,与SBR基体间作用力得到增强,与混炼前相比,混炼后试样的玻璃化转变温度、交联度和常规力学性能均得到提高,当CNTs加入量为50phr时,混炼后复合材料的拉伸强度和撕裂强度分别为13.1MPa和39.8kN/m,比混炼前试样分别提高了约80%和20%.     

炭纤维/鳞片石墨/氰酸酯复合材料的导热和力学性能（英文）

为了改善纤维增强树脂基复合材料厚度方向(Z向)热导率和纵向(X向)压缩强度,通过向氰酸酯树脂中加入不同质量分数的鳞片石墨填料进行树脂基体改性,并与中国TG800炭纤维复合制备成炭纤维复合材料。研究了鳞片石墨/氰酸酯复合物固化前的流变性能,固化后的导热率、力学性能,以及炭纤维/鳞片石墨/氰酸酯复合材料的热导率和力学性能。结果表明,未固化鳞片石墨/氰酸酯复合材料的流变复数黏度随着鳞片石墨添加量呈指数型增加,随着形变量的变化表现出佩恩(Payne)效应,体现了鳞片石墨在树脂基体中的联通网络的形成和破坏过程;固化后复合材料的热导率随着鳞片石墨添加量的增加呈线性增加。当鳞片石墨添加量为10 wt%时,鳞片石墨/氰酸酯拉伸模量从2.9 GPa提高到4.3 GPa,提高了48%,热导率提高了100%,炭纤维/鳞片石墨/氰酸酯复合材料的Z向导热率提高了127%,复合材料纵向压缩强度提高了31%。     

氮化硼/环氧树脂绝缘导热材料的制备及性能表征

将氮化硼(BN)粉末添加到环氧树脂(EP)中,制备了BN/EP绝缘导热复合材料,并对其热导率、抗拉强度、断面SEM(扫描电子显微镜)以及热失重进行分析,同时探究随着填充量的增加,复合材料的热导率和抗拉强度的变化趋势。结果表明:当20μm的BN的填充量为30%时,由其制备的复合材料的热导率在25℃时达到了0.92W/(m·K),抗拉强度为15.5MPa。并且随着BN填充量的增加,复合材料的热导率也逐渐增加,但抗拉强度逐渐降低。热失重分析说明随着BN填充量的增加,绝缘导热材料的起始分解温度并没有太大的变化,而复合材料的热失重量逐渐减少,分解温度逐渐升高。此外,随着添加BN粒径的增大,复合材料的热导率会增大,而抗拉强度却会减小。     

石墨烯/炭纤维/聚醚醚酮复合材料的制备及性能北大核心CSCD

使用层间喷涂法制备了石墨烯/炭纤维/聚醚醚酮(GR/CF/PEEK)复合材料,对材料微观形态、力学性能、热学以及电学性能进行了分析。结果表明,0.1 wt%的石墨烯的加入即可使复合材料的层间剪切强度(ILSS)从57.3 MPa增加到77.6 MPa,弯曲强度和弯曲模量分别从1 226.2 MPa、64.5 GPa增加到1 512.3 MPa、73.6 GPa。差示扫描量热结果证明少量石墨烯的加入能够提高复合材料基体的结晶度。同时复合材料的热导率和电导率也随着石墨烯含量的增加而增加,加入0.5 w t%的石墨烯,复合材料的热导率和电导率与未加入石墨烯相比分别增加了15.5%和73.1%。GR/CF/PEEK复合材料与CF/PEEK相比具有更优良的综合性能。     

碳纳米管/平面各向异性羰基铁复合材料的液相共混法制备及其电磁性能

采用机械球磨法制备了平面各向异性羰基铁（Planar Anisotropic Carbonyl Iron,PACI）,然后通过液相共混法制备了碳纳米管（CNTs）/PACI复合材料。采用同轴法测定CNTs/PACI复合材料在2~18 GHz频段内的复介电常数和复磁导率,研究了CNTs掺杂量对复合材料电磁性能的影响。结果表明：CNTs/PACI复合材料相对于PACI具有更高的复介电常数和衰减常数,随着CNTs质量分数的提高,复合材料的复介电常数和衰减常数逐渐增大,特征阻抗则逐渐减小。CNTs掺杂能够有效提高CNTs/PACI复合材料的吸波性能,通过调整厚度和CNTs掺杂量可以对复合材料的吸波性能进行有效调控。厚度为1.2 mm、CNTs质量分数为2wt%和厚度为1.6 mm、CNTs质量分数为0.5wt%的CNTs/PACI复合材料在Ku波段（12~18 GHz）的反射率均小于-10 dB;厚度为2.0 mm、CNTs质量分数为0.5wt%和1wt%的复合材料反射率小于-10 dB的频带宽分别为5.28 GHz（8.24~13.52 GHz）和5.04 GHz（7.52~12.56 GHz）,覆盖整个X波段（8~12 GHz）。     

Preparation and properties of the powder SBR composites filled with CNTs by spray drying process

Carbon nanotubes (CNTs) filled powder styrene-butadiene rubber (SBR) composites were prepared by spray drying of the suspension of CNTs in SBR latex. The powder was spherical like and uniform with an average diameter of less than 10 μm. The dispersion of CNTs in the rubber matrix was improved remarkably compared with that in the rubber composites obtained by the conventional mechanical mixing method. Further study about the effect of CNTs on the prepared SBR composites was performed by analyzing the vulcanization process of the SBR powder, thermal and mechanical properties of the vulcanized SBR composites. Differential scanning calorimeter (DSC) analysis indicated that the glass transition temperatures of SBR composites increased with the increasing ratio of CNTs. The vulcanization process showed that CNTs could decelerate the vulcanization of the SBR composites. Dynamic mechanical analysis indicated that the storage modulus of the composites was improved with the CNTs additions, especially when the CNTs addition exceeded 30 phr. Compared with pure SBR composites, the hardness, tensile and tear strengths of the composites filled with 60 phr CNTs enhanced 73.9%, 327.7% and 191.1%, respectively, which should be ascribed to the excellent mechanical properties of CNTs and uniform dispersion of CNTs in the rubber matrix.     

Preparation and properties of powder styrene-butadiene rubber composites filled with carbon black and carbon nanotubes

Carbon nanotubes (CNTs) and carbon black (CB) filled powder styrene-butadiene rubber (SBR) composites were prepared by spray drying of the suspension of CNTs and CB in SBR latex. The powders were sphere like and fine with uniform diameters of 10-15 μm. Experimental results showed that the introduction of CNTs into the matrix was beneficial to improve the security of the vulcanization of the rubber composites, and the dynamic and basic mechanical properties of the CNTs/SBR composites were better than those of CB/SBR and neat SBR composites. Observations on the microstructure of the composites indicated that CNTs were well dispersed in the matrix. Morphology of the fracture confirmed that the bonding between CNTs and rubber matrix was strong and load can be transferred to CNTs efficiently during the mechanical property tests. Moreover, the powder SBR composites containing well-dispersed CNTs could be perfect candidate as additives for other polymers.     

New Fabrication and Mechanical Properties of Styrene-Butadiene Rubber/Carbon Nanotubes Nanocomposite

A novel technology to prepare styrene-butadiene rubber(SBR)/carbon nanotubes(CNTs) composites was developed by combining a spray drying method and a subsequent mechanical mixing process.The cross-linking degrees of the vulcanized composites increased gradually with the additive CNTs contents.By comparing with those of the pure SBR composites,the mechanical properties such as tensile strength,tear strength and hardness of the composites filled with CNTs at certain contents were dramatically improved almost b...     

Thermal Conductivity Behavior of Carbon Nanotubes Reinforced Copper Matrix Composites

Carbon nanotubes (CNT) exhibit excellent thermal conductivity.Therefore they are potential reinforcements in composites materials for thermal management applications,where high thermal conductivity and low coefficient of thermal expansion (CTE) are required.In the present study,CNT/Cu composites containing CNTs varying from 0 vol.％ to 15 vol.％ were prepared,and their thermal conductivity behavior was studied in detail.The results indicated that the thermal conductivity of the composites shows no enhancement by the incorporation of CNTs.The presence of interfacial thermal resistance and high level of porosity are the main reasons for this low thermal conductivity.The well dispersed 0-10 vol.％ CNTs composites show a very close to the thermal conductivity of Cu.However,the addition of 15 vol.％ CNTs results in a rather low thermal conductivity of CNT/Cu composites due to the presence a high level of porosity induced by the formation of CNT clusters.The present paper also claims that a further substantial enhancement in thermal conductivity is only possible if the nanotubes are randomly oriented in the plane or if they are all aligned in one direction,for which the processing of CNTs-aligning in metal matrix should be developed.     

AlN-CNTs/聚酰亚胺复合材料的制备与性能

为了研究氮化铝(AlN)和碳纳米管(CNTs)对聚酰亚胺(PI)的导热、热学、力学性能的协同效应,采用湿法球磨和热压成型法制备了AlN/PI和CNTs-AlN/PI复合材料。利用X射线衍射仪、扫描电子显微镜对复合材料进行了物相分析和断面形貌表征,分别考察了AlN及其与CNTs协同对PI复合材料的导热、热学、力学性能的影响。结果表明,AlN和CNTs在PI基体中分散均匀且接触界面良好,AlN的加入可以显著地提高复合材料的导热性能,且对复合材料的热稳定性和力学性能有一定的提高;固定AlN的含量为10%,加入少量的CNTs可以提高复合材料的导热性能,但对复合材料的力学性能有一定的负面影响。     

碳纳米管增强镁基复合材料导热性能研究

镁及其合金是目前最轻的金属结构材料,合金化虽然提升了镁合金的力学性能,但导致其导热性能严重下降,限制了镁合金的应用。碳纳米管(CNTs)因具有优异的力学、热学等性能,是最理想的增强体之一,可以用于改善镁合金的力学性能和热学性能。采用粉末冶金法分别以纯Mg、Mg-9Al合金、Mg-6Zn合金为基体制备了不同CNTs含量的镁基复合材料,利用光学显微镜、扫描电子显微镜、透射电子显微镜对复合材料微观组织、基体与增强体界面及析出相进行表征,并对复合材料的拉伸性能和热学性能进行测试。研究结果表明,当CNTs质量分数不超过1.0%时,可提高纯镁基复合材料的导热性能,力学性能仅有稍微降低;将CNTs添加到Mg-9Al合金中,可以促进纳米尺度β-Mg 17 Al 12相在CNTs周围析出,降低了Al在Mg基体中的固溶度,使CNTs/Mg-9Al复合材料的导热性能有所提高。此外,在CNTs/Mg-6Zn复合材料界面处存在C原子和Mg原子的相互嵌入区,这种嵌入型界面不仅有利于复合材料力学性能的提高,也使CNTs起到加速电子移动的“桥”的作用,有利于该复合材料热导率的提高。当CNTs质量分数为0.6%时,CNTs/Mg-6Zn复合材料具有较为优异的热学性能和力学性能,其热导率为127.0 W/(m·K),抗拉强度为303.0 MPa,屈服强度为204.0 MPa,伸长率为5.0%。     

超声分散制备天然橡胶/丁苯橡胶/炭黑/碳纳米管纳米复合材料

通过超声分散制备了分散均匀的碳纳米管(CNTs)/天然橡胶母料,利用母料制备了天然橡胶(NR)/丁苯橡胶(SBR)/炭黑(CB)/碳纳米管复合材料。通过比较常规搅拌、双辊混炼和超声分散三种方法对碳纳米管的分散及对复合材料性能的影响,表明超声分散能实现碳纳米管在基体中均匀分散,CNTs和CB的协同作用提高了复合材料的力学性能,当CB/CNTs之比为37/3时力学性能最高,与未加CNTs增强的体系相比,拉伸强度提高了6.4%。当CNTs含量为7phr,与未加CNTs的体系相比,压缩模量提高了20%。     

CNTs/Mg-9Al复合材料微观组织、力学及导热性能EI北大核心

研究了CNTs的加入对Mg-9Al镁基复合材料时效行为的影响,探讨了时效处理过程中微观组织、力学性能及导热性能的演变规律。结果表明:添加的CNTs增大了基体合金中铝元素的固溶度,并在时效过程中限制晶界的迁移,在二者共同作用下,促进基体中连续β-Mg_(17)Al_(12)相的析出,且随着CNTs含量的增加,连续析出的比例增大;与基体呈共格关系的杆状连续析出相能够有效地阻碍位错运动,提高复合材料的力学性能,其中峰时效态0.4CNTs/Mg-9Al复合材料的屈服强度、抗拉强度、热扩散系数和热导率分别为275 MPa,369 MPa,34.5 mm^(2)/s和68.4 W/(m·K),相较于时效前Mg-9Al合金分别提升了17%,23%,43%和45%。